The Holley 2300 500 cfm did not, but you can find a speed shop with the tooling to install these if desired. The Holley 2010 two barrel did come with them, but since it used a throttle body design similar to the Carter carbs, it as prone to warping and fell out of favor (still lots of them around on craigslist and ebag). The Holley 2300 625 cfm carb came with a similar style booster but that dude is not going to be friendly on a slant for the most part without lots of mods and tinkering.

Not sure that the 500 can be tamed enough to get that kind of mileage, it compares to the 390 cfm 4 barrel in flow vs. pressure drop, but the 390 should get better mileage over the 500 since it has less flow in the primaries and only opens the secondaries on demand, allowing for a much more staged use of the carb, the 500 is more like the primaries on the bigger 4 barrels and once you open the throttle it's lots of flow or nothing whether the engine is built for it or not...

Make sure you have the Emmanuel book on Holley's so you get familiar with what to tune and troubleshooting, it'll come in handy.

-D.Idiot